package cn.tedu.coolshark.filter;

import cn.tedu.coolshark.entity.User;

import javax.servlet.*;
import javax.servlet.annotation.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;

@WebFilter(filterName = "MyFilter",urlPatterns = {"/insertProduct.html","/admin.html"})
public class MyFilter implements Filter {

    //当接收到请求时会执行此方法, 需要在此方法中判断 是否允许访问Controller或静态资源
    public void init(FilterConfig config) throws ServletException {
    }

    //当过滤器销毁时执行的方法
    public void destroy() {
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws ServletException, IOException {

        //将父类类型转换成子类类型
        HttpServletRequest st = (HttpServletRequest) request;
        HttpServletResponse se = (HttpServletResponse) response;
        //得到会话对象
        HttpSession session = st.getSession();
        //从会话对象中得到登录成功时保存的用户对象
        User user = (User) session.getAttribute("user");
        if (user!=null){//代表登录过
            chain.doFilter(request,response);//放行
        }else{//代表未登录
            se.sendRedirect("/login.html");//重定向 让客户端重新指向登录页面
        }
        System.out.println("过滤器执行了");
        chain.doFilter(request, response);//放行 允许访问资源

    }

}
